Formulations comprising mercury-containing reagents for detecting disease

ABSTRACT

Disclosed herein is a formulation for detecting a species indicative of a disease in a patient. The formulation comprises a mercury-containing reagent which, when contacted with a fluid sample from the patient, colourimetrically indicates whether the fluid sample contains the species. The mercury-containing reagent is contained within a non-flowing carrier which, upon exposure to the fluid sample, causes rapid mixing of substantially all of the mercury-containing reagent and the fluid sample.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional patent application of and claimspriority to the U.S. patent application Ser. No. 15/548,767 filed onAug. 4, 2017, which claims priority to the PCT International ApplicationNo. PCT/AU2016/050067 filed on Feb. 5, 2016, which claims priority tothe Australian Patent Application No. 2015900347 filed on Feb. 5, 2015.The entirety of the contents of these applications are incorporated byreference herewith.

TECHNICAL FIELD

The present invention relates to a formulation, kit and method fordetecting a species indicative of a disease in a patient. In aparticular embodiment, the present invention relates to a formulation,kit and method for detecting tyrosine or its metabolites in a patient'surine.

BACKGROUND ART

The presence of certain species in a person's bodily fluids can often beindicative of that person having a disease or condition. Early diagnosisof such a disease or condition can dramatically increase the likelihoodof any treatment regimen being successful, and it is an ongoingchallenge in the medical field to develop new early diagnosis tests.Such early diagnosis tests are preferably relatively simple to performand provide reliable results relatively quickly.

Tests for colorectal cancer such as the faecal occult blood (FOB) test,for example, are available. However, the FOB test relies on a patient'sfaeces containing blood (from a bleeding polyp), which does not occurall the time and is therefore prone to false negatives. Indeed, somereports have indicated that the sensitivity of the FOB test fordetecting colorectal cancer is at best 25%. The FOB test also requires afaecal sample to be collected, with many tests not being completed dueto patients being reluctant to obtain faecal samples (less than 20% ofthe FOB kits freely supplied to Australians aged 50-75 are returned).Furthermore, once obtained, the faecal sample needs to be analysed in alaboratory, which complicates the procedure and increases its cost.

The presence of phenolic compounds such as tyrosine and its metabolitesin a patient's urine can be indicative of the patient having a cancer,for example, colorectal cancer. Tests for tyrosine and its metabolitesusing Millon's Reagent or variations thereof are known. Millon's Reagentis obtained by dissolving metallic mercury in nitric acid and dilutingwith water. When Millon's Reagent is exposed to a fluid samplecontaining phenolic compounds (e.g. tyrosine and its metabolites), ared-brown precipitate forms. The presence of such a red-brownprecipitate following exposure of the patient's urine to Millon'sReagent would prompt the patient to undergo further tests.

As Millon's Reagent contains mercury, it needs to be very carefullyhandled. Typically, the Millon's Reagent is provided in a glass ampoulewith a frangible portion. Immediately before use, the ampoule is brokenand the urine sample is added to the Millon's Reagent. However, thebroken glass ampoule has sharp edges and presents a health hazard, andthere is a risk that the user may be exposed to mercury (e.g. due tospillage). Furthermore, if the ampoule is not broken with a good sharpknock, it may shatter. For at least these reasons, existing testsinvolving Millon's Reagent are not really suitable for non-specialiseduse.

U.S. Pat. No. 5,094,836 discloses using an improved form of Millon'sReagent for screening patients for the presence of cancer. The improvedform of Millon's Reagent relates mainly to providing a mixed Hg—Nicomposition, which improves the stability of the coloured precipitateformed in the presence of tyrosine. U.S. Pat. No. 5,094,836 alsodiscloses that the composition may be admixed with a material to form agel, with the resultant jelly phase advantageously reducing thehazardous conditions posed by a mercury-containing solution. However, itis acknowledged that the reactive sensitivity of the jelly is apt todecline somewhat compared to that of the solution and, in the examplesprovided, it was noted that precipitates only formed at the boundary ofthe jelly and urine phases.

SUMMARY OF INVENTION

In a first aspect, the present invention provides a formulation fordetecting a species indicative of a disease in a patient. Theformulation comprises a mercury-containing reagent which, when contactedwith a fluid sample from the patient, colourimetrically indicateswhether the fluid sample contains the species. The mercury-containingreagent is contained within a non-flowing carrier which, upon exposureto the fluid sample, causes rapid mixing of substantially all of themercury-containing reagent and the fluid sample.

In some embodiments, the non-flowing carrier may, for example, be (orcomprise) a gel carrier which, upon exposure to the fluid sample,rapidly disintegrates to release substantially all of themercury-containing reagent. In alternative embodiments, the non-flowingcarrier may, for example, be (or comprise) an absorbent material which,upon exposure to the fluid sample, rapidly absorbs the fluid sample.

The inventor recognised that providing the mercury-containing reagent ina non-flowing carrier such as a gel carrier or an absorbent material hasa number of advantages, particularly user safety, but that theseadvantages must not be at the expense of preventing substantially all ofthe mercury-containing reagent from being able to rapidly mix with thefluid sample upon exposure to the fluid sample. Experiments have shown,for example, that reactions which occur only at the boundary of jellyand urine phases are far more prone to false (positive or negative)results. The inventor recognised that unless the mercury-containingreagent and fluid sample are able to intimately mix relatively quickly,then the risk of false or inconclusive results is of concern.Embodiments of the present invention provide a very selective andreliable test for the presence of species indicative of a disease in afluid sample from a patient.

As would be appreciated, rapid disintegration of the gel carrier veryquickly results in a vast majority of the mercury-containing reagentbeing available to react with any species in the patient's fluid sample,thereby providing for an almost as rapid and precise analysis as thatwhich occurs when the mercury-containing reagent is provided in liquidform. The inventor realised that if the gel carrier does not rapidlydisintegrate, then there is a significant risk that the reactions whichoccur and colourimetrically indicate the presence of the species willeither not occur to an extent sufficient to be visually detectable orthat they will occur only in dispersed portions of the mixture, furtherhindering visual detection of the colour change.

Similarly, rapid absorption of the fluid sample by the absorbentmaterial very quickly results in a vast majority of themercury-containing reagent being available to react with any species inthe patient's fluid sample, thereby providing for an almost as rapid andprecise analysis as that which occurs when the mercury-containingreagent is provided in liquid form.

In some embodiments, the fluid sample is a urine sample from a patient.Urine samples are relatively easy to obtain, especially by the patientthemselves, which makes detecting the species indicative of a diseaseeasier from a logistical point of view. Patients also tend to be morereceptive to collecting urine samples than faecal samples, so urinetesting would therefore be expected to result in a greater degree ofpatient compliance and hence completed tests. Patients may even be ableto self-test for the presence of species indicative of a disease intheir urine.

In some embodiments, the species indicative of a disease in a patient istyrosine (or one or more of its metabolites). As noted above, tyrosineand its metabolites have been found to be elevated in the urine ofpatients having tumours, especially tumours associated withgastrointestinal cancers such as colorectal cancer (although othermalignant tumours can also result in tyrosine and its metabolites ormetabolites of tryptophan being elevated in a patient's urine, asdiscussed below). A positive test using embodiments of the presentinvention would prompt the patient to seek more specialised medicaladvice.

In some embodiments, the gel carrier rapidly disintegrates to releasesubstantially all of the mercury-containing reagent within less thanabout 1 minute after being exposed to the fluid sample. In someembodiments, the absorbent material absorbs the fluid sample within lessthan about 1 minute after being exposed to the fluid sample.

In some embodiments, the gel carrier is a substance that is miscible in,dissolves in or otherwise rapidly disperses when exposed to the fluidsample. In some embodiments, for example, the gel carrier may be (or maycomprise) a hydrogel. In some embodiments, the gel carrier may be formedfrom any one of the following: polyacrylamides, carboxy methylcellulose,polyvinyl alcohol, poly(acrylamide-co-maleic acid),poly(vinylpyrrolidone), alginates, carbomers, polyoximers, natural andsynthetic gums, and mixtures thereof In embodiments where the gelcarrier includes mixtures of substances, the substances can be selectedto provide a resultant gel carrier with improved properties (e.g.improved disintegration properties, reduced interactions with specificmercury-containing reagents, better stability in highly acidicconditions, etc.).

In some embodiments, the absorbent material may be (or may comprise) afibrous material. In some embodiments, the absorbent material may beformed from any one of the following: paper pulp, cotton wool,cellulosic fibres, synthetic fibres, super absorbent polymers andpolyvinyl alcohol fibres. In some embodiments, combinations of materialsmay be used in order to provide an absorbent material having improvedproperties.

In some embodiments, the mercury-containing reagent comprises mercurysalts dissolved in an acid solution (e.g. comprising one or more mineralacids). Such a reagent is known as Millon's Reagent which, as notedabove, has been used to detect phenolic compounds such as tyrosine andits metabolites. The production of a red-brown colouration orprecipitate when the formulation of the present invention and fluidsample from the patient are mixed is indicative of the presence oftyrosine (and/or its metabolites) in the sample. As discussed above, thepresence of significant quantities of tyrosine (and/or its metabolites)in a patient's urine can be indicative of cancer, and a positive testusing embodiments of the present invention should prompt the patient toseek more specialised healthcare.

In some embodiments, the mercury-containing reagent may containadditional components. Such additional components, and the advantageousproperties they impart on the resultant formulation, will be discussedin further detail below.

In some embodiments, the formulation may further comprise agents such asdispersing agents, solubilising agents, wetting agents or emulsifyingagents to improve (or advantageously alter) properties of the gelcarrier (e.g. its disintegration properties) or the absorbent material(e.g. its absorbing properties). Any such additional agents are alsocarried in the non-flowing carrier. The advantageous properties theyimpart on the resultant formulation will be discussed in further detailbelow.

In a second aspect, the present invention provides a formulation fordetecting a species indicative of a disease in a patient. Theformulation comprises a mercury-containing reagent which, when contactedwith a fluid sample from the patient, colourimetrically indicateswhether the fluid sample contains the species. The formulation alsocomprises a gel carrier in which the mercury-containing reagent iscontained but which, upon exposure to the fluid sample, rapidlydisintegrates to release substantially all of the mercury-containingreagent.

In a third aspect, the present invention provides an absorbent pad fordetecting a species indicative of a disease in a patient. The padcomprises an absorbent material adapted to rapidly absorb a fluid samplefrom the patient. The absorbent material contains a mercury-containingreagent capable of colourimetrically indicating whether the fluid samplefrom the patient contains the species upon contact with the fluidsample. Upon exposure of the pad to the fluid sample, the absorbentmaterial rapidly absorbs the fluid sample, thereby causing rapid mixingof substantially all of the mercury-containing reagent and the fluidsample.

Embodiments of the second and third aspects of the present invention maybe as described herein with respect to the first aspect of the presentinvention in which the non-flowing carrier is a gel carrier and anabsorbent material, respectively.

In a fourth aspect, the present invention provides a kit for detecting aspecies indicative of a disease in a patient. The kit comprises amercury-containing reagent which, when contacted with a fluid samplefrom the patient, colourimetrically indicates whether the fluid samplecontains the species, and a non-flowing carrier in which themercury-containing reagent is contained but which, upon exposure to thefluid sample, causes rapid mixing of substantially all of themercury-containing reagent and the fluid sample. The kit also comprisesa container in which the non-flowing carrier and the mercury-containingreagent is contained.

Embodiments of the mercury-containing reagent and non-flowing carrier inthe kit of the fourth aspect of the present invention may be asdescribed herein with respect to the first aspect of the presentinvention.

In some embodiments, the container may be adapted to receive the fluidsample from the patient. In some embodiments, the container may beadapted to receive a predetermined volume of the fluid sample from thepatient.

Advantageously, embodiments of the kit of the present invention may beprovided in a form simple, safe and reliable enough for use by patientsat home (e.g. with a urine sample), with instructions provided with thekit emphasising the importance of the patient seeking specialisedmedical advice in the event of the kit displaying a positive result.

In some embodiments, the container may comprise a plurality of cells,with at least one of the plurality of cells containing the non-flowingcarrier and the mercury-containing reagent; and at least one other ofthe plurality of cells containing a control sample of the non-flowingcarrier that does not contain the mercury-containing reagent. Theplurality of cells are configured to allow a visual comparison of thecolour in each of the plurality of cells.

In such embodiments, a direct visual comparison can be made between atleast two of the cells in the container in order to provide an even morereliable result because factors such as the colour of a patient's urine(for example) or potential colour blindness of the patient (or personassessing the results) are accounted for.

In a fifth aspect, the present invention provides a method of detectinga species indicative of a disease in a patient. The method comprisesexposing a fluid sample from the patient to the formulation according tothe first or second aspect of the present invention, the absorbent padof the third aspect of the present invention or the kit of the fourthaspect of the present invention to form a mixture; and observing acolour of the mixture to determine whether the fluid sample contains thespecies.

In a sixth aspect, the present invention provides a kit for detecting aspecies indicative of a disease in a patient. The kit comprises acontainer containing the formulation according to the first or secondaspect of the present invention and adapted to receive a fluid samplefrom the patient. In some embodiments, the kit may also comprise acolour chart for assessing whether the fluid sample contains thespecies.

In a seventh aspect, the present invention provides the formulationaccording to the first or second aspect of the present invention or akit of the third or fifth aspect of the present invention for use indetecting a species indicative of a disease in a patient.

BRIEF DESCRIPTION OF THE DRAWINGS

Specific embodiments of the present invention will be described belowwith respect to the accompanying drawing, in which:

FIG. 1 shows a kit for detecting a species indicative of a disease in apatient in accordance with an embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

As noted above, the present invention provides formulations fordetecting a species indicative of a disease in a patient.

In a first aspect, the formulation comprises a mercury-containingreagent which, when contacted with a fluid sample from the patient,colourimetrically indicates whether the fluid sample contains thespecies. The mercury-containing reagent is contained within anon-flowing carrier which, upon exposure to the fluid sample, causesrapid mixing of substantially all of the mercury-containing reagent andthe fluid sample.

In a second aspect, the formulation comprises a mercury-containingreagent which, when contacted with a fluid sample from the patient,colourimetrically indicates whether the fluid sample contains thespecies. The formulation also comprises a gel carrier in which themercury-containing reagent is contained but which, upon exposure to thefluid sample, rapidly disintegrates to release substantially all of themercury-containing reagent.

The present invention also provides an absorbent pad (or mat) fordetecting a species indicative of a disease in a patient. The padcomprises an absorbent material adapted to rapidly absorb a fluid samplefrom the patient. The absorbent material contains a mercury-containingreagent capable of colourimetrically indicating whether the fluid samplefrom the patient contains the species upon contact with the fluidsample. Upon exposure of the pad to the fluid sample, the absorbentmaterial rapidly absorbs the fluid sample, thereby causing rapid mixingof substantially all of the mercury-containing reagent and the fluidsample.

The formulations and absorbent pad of the present invention can be usedto detect a species indicative of a disease in a patient. Any speciesthat can be detected colourimetrically by exposure to amercury-containing reagent may be detected using the formulation of thepresent invention.

In one class of embodiments, the species indicative of a disease in apatient is tyrosine (4-hydroxyphenylalanine) and/or its metabolites. Thepresence of elevated quantities of tyrosine (and/or its metabolites) ina fluid sample obtained from a patient can be indicative of the patienthaving tumours, especially tumours associated with gastrointestinalcancers such as colorectal cancer. Tyrosine is used by cells tosynthesise proteins, and elevated levels of tyrosine (and/or itsmetabolites) in the patient's fluid sample can be indicative of theirbody producing a larger than usual number of cells, as is often the casewith fast-growing tumours. Other tumours which might cause elevatedquantities of tyrosine in a patient's fluid sample include prostatecancer, ovarian cancer, bladder cancer, breast cancer, cervical cancer,stomach cancer, lung cancer, laryngeal cancer, oesophageal cancer,biliary cancer, hepatoma, duodenal cancer, bronchogenic cancer and bonemarrow cancer. In some embodiments, the species indicative of a diseasein a patient may also include metabolites of tryptophan, such as5-hydroxytryptamine (serotonin) and 5-hydroxyindoleacetic acid (5-HIAA).Cancer cells metabolise large amounts of tryptophan and the presence ofelevated levels of tryptophan metabolites in a patient's fluid samplemay be indicative of cancer.

This class of embodiments is described in further detail below, but itis important to recognise that the present invention is not limited todetecting only tyrosine or its metabolites and, in some embodiments,metabolites of tryptophan. For example, it is envisaged that embodimentsof the present invention may also be used to detect raised levels ofurinary nucleosides such as pseudouridine,2-pyridone-5-carboxamide-N1-ribofuranoside, N2,N2-dimethylguanine,1-methylguanosine, 2-methylguanosine and 1-methyladenosine, the presenceof which in fluid samples from patients may be used for early detectionand clinical diagnosis of cancers such as colorectal, gastric, liver,lung and breast cancers.

In one class of embodiments, the fluid sample is a urine sample from thepatient. As noted above, urine samples are relatively easy to obtain andoften contain species indicative of a disease in a patient. Typically,the urine sample is obtained mid-stream (any potential contaminants willgenerally be present in a patient's initial urine stream) from thepatent's first pass urination in the morning (which contains the highestconcentration of markers). This class of embodiments is described infurther detail below, but it is important to recognise that the presentinvention is not limited to detecting the species in only urine. Forexample, it is envisaged that embodiments of the present invention maybe used to detect the species in saliva, blood and, despite thecollection issues discussed above, faecal matter.

The formulation comprises a mercury-containing reagent which, whencontacted with a fluid sample from the patient, colourimetricallyindicates whether the fluid sample contains the species. That is, whenthe fluid sample is mixed with the mercury-containing reagent, areaction that results in a colour change occurs. The reaction may, forexample, result in the formation of a coloured precipitate.Alternatively (or in addition), the reaction may result in a colourchange of the mixture.

In some embodiments, the mercury-containing reagent may comprise mercurydissolved in an acid solution. Such a reagent is known as Millon'sReagent which, as noted above, has reliably been used to detect phenoliccompounds (such as tyrosine) in fluid samples for many years. The acidsolution is typically a mineral acid (preferably a strong mineral acid),such as nitric acid, sulphuric acid, or a combination thereof.

In some embodiments, the mercury-containing reagent may comprisedifferent forms of mercury (e.g. salts having different oxidation stateslike Hg⁺ and Hg²⁺) or additional components, which impart advantageousproperties to the reagent or which make it more suitable for detecting aparticular species. For example, the mercury-containing reagent maycomprise a source of Hg⁺ ions and a source of Hg²⁺) ions (e.g.mercury(II) sulphate and mercurous nitrate), typically in an acidsolution. Such a reagent is an improved form of Millon's Reagent, andhas a greater sensitivity to tyrosine and its metabolites. Anyprecipitates that form may also be more stable than would be the casefor reagents containing just Hg⁺.

In some embodiments, for example, the mercury containing reagent maycomprise between about 10 and 90 wt % mercury, for example, betweenabout 20 and 80 wt %, between about 30 and 70 wt %, between about 40 and60 wt % mercury. In some embodiments, for example, the mercurycontaining reagent may comprise about 10 wt %, 20 wt %, 30 wt %, 40 wt%, 50 wt %, 60 wt %, 70 wt %, 80 wt % or 90 wt % mercury. In embodimentswhere the mercury containing reagent comprises Hg⁺ and Hg²⁺, the ratioof Hg⁺: Hg²⁺ may be from 0.1 to 1:0.1 to 1.0.

The mercury-containing reagent may also include a source of Ni²⁺ ions,for example a nickel salt such as nickel sulphate, in order to improvethe stability of the precipitate that forms in the presence of thespecies, and thereby improve the reliability of the test (precipitateshaving enhanced stability are more likely to reliably form and, onceformed, last for longer, therefore making them easier to visuallydetect). If present, the mercury containing reagent may include nickelin an amount of between about 0.1 to 0.5 parts by weight to 1 part byweight mercury.

The mercury-containing reagent may also include a source of Cd²⁺ ions,for example a cadmium salt such as cadmium sulphate, in order to improvethe stability of the precipitate that forms in the presence of thespecies and thereby improve the reliability of the test. If present, themercury containing reagent may include cadmium in an amount of betweenabout 0.05 to 0.5 parts by weight to 1 part by weight mercury.

In embodiments where the species being detected includes tyrosine or itsmetabolites and, optionally, metabolites of tryptophan themercury-containing reagent may also include a compound such as1-nitroso-2-naphthol. 1-nitroso-2-naphthol complexes with 4-hydroxylatedphenolic acids such as tyrosine and the tryptophan metabolites serotoninand 5-HIAA to form a product having a red colour (the product is adifferent product to that formed when the species indicative of adisease reacts with the mercury-containing reagent). Elevated levels of5-HIAA in patient's fluid samples (especially urine samples) are welldocumented in gastrointestinal tumours, and the presence of1-nitroso-2-naphthol in the mercury-containing reagent may thereforehelp to enhance the sensitivity of the formulation to detecting speciesindicative of a disease. If present, the mercury containing reagent mayinclude 1-nitroso-2-naphthol in an amount of between about 0.05 to 0.5parts by weight to 1 part by weight mercury.

The mercury-containing reagent may also include diazonium compounds,such as benzenediazonium chloride, 2,4-dichloroaniline diazonium salts,2,6-dichlorobenzene-diazonium-tetrafluoroborate andp-nitrobenzene-diazonium-p-toulenesulfonate, which can complex withtyrosine and its metabolites, even under highly acidic conditions, inorder to increase the sensitivity of the reagent.

The mercury-containing reagent may also include tetrazonium salts, suchas tetrazonium diaminodiphenylamine. Such salts can form a fluorescentred dye in the presence of tyrosine and tryptophan.

The exact composition of the mercury-containing reagent will depend onfactors such as the nature of the fluid sample, non-flowing carrier andthe species to be detected. It is within the ability of a person skilledin the art to prepare an appropriate mercury-containing reagent for usein the present invention.

The amount or proportion of mercury-containing reagent contained in theformulation or absorbent pad will depend on factors such as the expectedconcentration of the species in the sample, the volume of the sample,the form of the non-flowing carrier, etc. It is within the ability of aperson skilled in the art to estimate the amount or proportion ofmercury-containing reagent required for any given formulation orabsorbent pad and, if necessary, conduct routine tests to determine ifthe estimated proportion is appropriate.

In embodiments where the non-flowing carrier is a gel, for example, theformulation may comprise between about 20 and about 80 vol %, e.g.between about 30 and about 70 vol %, between about 40 and about 60 vol%, between about 30 and about 80 vol %, between about 50 and about 80vol %, of the mercury-containing reagent. In some embodiments, theformulation may comprise about 20 vol %, about 30 vol %, about 40 vol %,about 50 vol %, about 60 vol %, about 70 vol % or about 80 vol % of themercury-containing reagent.

In some embodiments, for example, the formulation or absorbent pad maycomprise between about 0.01 and about 5 mL, between about 0.5 and about3 mL, between about 1 and about 2 mL or between about 0.5 and about 1.5mL (e.g. about 1 mL) of the mercury-containing reagent.

Gel Carrier

In some embodiments of the present invention, the mercury-containingregent is contained within a gel carrier. The mercury-containing reagentis safely contained within the gel carrier during normal storage andhandling conditions. Upon exposure to the fluid sample, however, the gelcarrier is adapted to rapidly disintegrate and release substantially allof the mercury-containing reagent. The gel carrier may disintegrate, forexample, because it is miscible in the fluid sample. The gel carrier maydisintegrate, for example, because it dissolves in the fluid sample. Thegel carrier may disintegrate, for example, because it disperses into thefluid sample.

The gel carrier must rapidly disintegrate in order to rapidly releasesubstantially all of the mercury-containing reagent, so that it can thenreact with the species (if present) in the patient's fluid sample. Insome embodiments, for example, it is envisaged that determining whetherthe sample contains the species will take about 5 minutes. Thus, inorder for the mercury-containing reagent to have time to react with thespecies (if present) to produce its colorimetric response, a substantialportion of the mercury containing reagent must be released from the gel(so it can react with the species) in significantly less than 5 minutes.The time taken for the gel carrier to disintegrate will depend onfactors such as the relative volumes of the fluid sample and gelcarrier, the nature of the fluid sample, the acidity of themercury-containing reagent, etc. It is envisaged, however, thatsubstantially all of the mercury-containing reagent would ideally bereleased within less than about 1-3 minutes (e.g. 1-2 min) afterexposure to the fluid sample. In some embodiments, the time taken forthe gel carrier to disintegrate after exposure to the fluid sample isabout 180 seconds, about 150 seconds, about 120 seconds, about 90seconds, about 60 seconds or about 30 seconds.

Whilst it will depend on many factors, in the context of the presentinvention, “substantially all of the mercury-containing reagent” isintended to mean more than about 80%, 85%, 90% or 95% of themercury-containing reagent contained in the gel carrier is releasedwithin the specified time.

The gel carrier may be formed from any substance or combination ofsubstances, provided that it is capable of forming a semi-solid immobile(substantially non-flowing) gel that can carry the mercury-containingreagent (noting that, in some embodiments, this may be highly acidic)for an appropriate storage time, but which will rapidly disintegrate torelease substantially all of the mercury-containing reagent uponexposure to the fluid sample. Despite having to rapidly disintegrateupon exposure to the fluid sample, the gel carrier must, in normalhandling and use, allow very little (if any) mercury to escape. It iswithin the ability of a person skilled in the art, using the teachingsprovided herein and routine experiments, to determine whether aparticular gel carrier is suitable for use in the present invention.

Whilst the gel does not need to be a solid and may have some flowingability, it must be sufficiently viscous so that it is not able toreadily flow at temperatures expected to be encountered in normal use,even in the event of a container containing the formulation beingaccidentally knocked over. For example, in some embodiments, the gelcarrier may have a viscosity ranging from about 50,000 to about1,000,000cps at ambient temperature. The viscosity of the gel carriermay, for example be about 50,000cps, about 100,000cps, about 150,000cps,about 200,000cps, about 250,000cps, about 300,000cps, about 350,000cps,about 400,000cps, about 450,000cps, about 500,000cps, about 550,000cps,about 600,000cps, about 650,000cps, about 700,000cps, about 750,000cps,about 800,000cps, about 850,000cps, about 900,000cps, about 950,000cpsor about 1,000,000cps.

The gel carrier may be a substance that rapidly disintegrates (e.g.disperses) when exposed to an aqueous solution. One suitable class ofsubstances are hydrogels, which are a network of polymer chains that arehydrophilic, and are highly absorbent (they can contain over 90% water)natural or synthetic polymeric networks. The mercury-containing reagentcan be carried within the interstitial spaces defined between thepolymer chains.

The inventor has found that not all gels are able to be used in thepresent invention (i.e. will meet the functional requirements of the gelcarrier). Indeed, the present invention relates, at least in part, tothe inventor challenging the conventional wisdom that carrying Millon'sReagent in a gel does not work (e.g. as is noted in U.S. Pat. No.5,094,836), and surprisingly and unexpectedly discovering thatmercury-containing reagents such as Millon's Reagent can, in fact becarried by a gel. The inventor realised that substances such as gelatineand agar gels are generally not suitable for use in the presentinvention, because these are either not stable at low pH or do notrapidly disintegrate upon exposure to the patient's fluid sample.However, the gels specifically disclosed herein are suitable for use inthe present invention, and routine tests carried out by a person skilledin the art in light of the teachings of the present invention willindicate the suitability of any given gel carrier for use in the presentinvention.

In some embodiments, the gel carrier is formed from any one or acombination of polyacrylamides, carboxy methylcellulose, polyvinylalcohol, poly(acrylamide-co-maleic acid), poly(vinylpyrrolidone),alginates, carbomers, polyoximers, natural and synthetic gums. Inembodiments where the gel carrier includes a combination of substances,those substances can be selected to provide a resultant gel carrier withimproved disintegration properties, reduced likelihood of interactionswith specific mercury-containing reagents, increased stability in acidicconditions, or the like. Mixtures of gel-forming substances may alsoenable better dispersion of interacting components in the formulationand patient's fluid sample, potentially improving the detection ofspecific target markers.

Specific examples of substances which can be used to form the gelcarrier include PVP K30 (a synthetic polyvinylpyrrolidone polymer),PLURONIC F88 (a difunctional block copolymer surfactant terminating inprimary hydroxyl groups), PVPP (polyvinylpolypyrrolidone—a highlycross-linked version of PVP), PAM SAP (a polyacrylamide super absorbentpolymer) and CMC HV (a high-viscosity, technical-grade sodiumcarboxymethyl cellulose).

The proportion of gel carrier to mercury-containing reagent in theformulation will depend on factors such as the amount of themercury-containing reagent to be contained, the expected concentrationof the species in the sample, the volume of the sample, etc. It iswithin the ability of a person skilled in the art to estimate theproportion of gel carrier required for any given formulation and, ifnecessary, conduct routine tests to determine if the estimatedproportion is correct.

In some embodiments, for example, the formulation may comprise betweenabout 0.5 mL to about 2.0 mL of the gel carrier. In some embodiments,for example, the formulation may comprise between about 20 and about 80vol %, e.g. between about 30 and about 70 vol %, between about 40 andabout 60 vol %, between about 30 and about 80 vol %, between about 50and about 80 vol %, of the gel carrier. In some embodiments, theformulation may comprise about 20 vol %, about 30 vol %, about 40 vol %,about 50 vol %, about 60 vol %, about 70 vol % or about 80 vol % of thegel carrier.

Typically, the gel carrier would be formed shortly after mixing with themercury-containing reagent (or precursors of the mercury-containingreagent) so that, upon vigorous stirring, a substantially homogeneousdispersion of the mercury-containing reagent within the gel carrier isobtained. In effect, the mercury-containing reagent is admixed with thegel carrier. It will be appreciated, however, that any method whichresults in the mercury-containing reagent being safely contained withinthe gel carrier would be suitable.

Absorbent Material

In some embodiments, the mercury-containing regent is contained withinan absorbent material which, when exposed to the fluid sample, isadapted to rapidly absorb the fluid sample. Any absorbent material whichis capable of remaining stable whilst carrying the (potentially highlyacidic) mercury-containing reagent in a secure manner (i.e. withsubstantially no leakage) during storage, but rapidly absorbing thefluid sample once exposed to it may be used. Ideally, the absorbentmaterial should not chemically or physically change substantiallythroughout the shelf-life of the formulation. Any change in colour ofthe mixture post-exposure (e.g. when a red precipitate forms) must alsobe clearly visible to the user, despite any absorbent material that mayremain.

The absorbent material may utilise any suitable mechanism to absorb thefluid sample (e.g. capillary action or swelling), provided that itcauses rapid absorption of the fluid sample whereupon the fluid sampleand mercury-containing regent become well mixed. In some embodiments,for example, the absorbent material may absorb the fluid sample into itsmatrix, where reactions take place and any resultant colour change isvisible in the material itself In some embodiments, for example,absorbing the fluid sample may cause the absorbent material to releasethe mercury-containing regent, where any resultant colour change isvisible in the supernatant liquid (and possibly contrasted against anyremaining absorbent material). In some embodiments, for example,absorbing the fluid sample may cause the absorbent material to swell,dissolve or disintegrate, where any resultant colour change is visiblein the resultant liquid.

The absorbent material must rapidly absorb the fluid sample. In someembodiments, for example, it is envisaged that determining whether thesample contains the species will take about 5 minutes. Thus, in orderfor the mercury-containing reagent to have time to react with thespecies (if present) to produce its colorimetric response, a substantialportion of the fluid sample must be absorbed by the absorbent material(so any species in the sample can react with the mercury-containingreagent) in significantly less than 5 minutes. The time taken for theabsorbent material to absorb the fluid sample will depend on factorssuch as the relative volume of the fluid sample and size of theabsorbent material, the nature of the fluid sample, the acidity of themercury-containing reagent, etc. It is envisaged, however, that thefluid sample (or at least an appropriate volume thereof) would ideallybe absorbed within less than about 1-3 minutes (e.g. 1-2 min) after theabsorbent material was exposed to the fluid sample. In some embodiments,the time taken for the absorbent material to absorb the fluid sample isabout 180 seconds, about 150 seconds, about 120 seconds, about 90seconds, about 60 seconds or about 30 seconds.

The absorbent material may, for example, be a fibrous material (e.g.provided as a pad or mat) or a compact powder (e.g. provided as atablet). The absorbent material may, for example, be formed from any oneof the following materials: paper pulp, cotton wool, cellulosic fibres(e.g. bleached hemp and bamboo fibres), synthetic fibres (e.g. inmicrofiber form so that they absorb via capillary action), superabsorbent fibres or polymers (e.g. based on acrylic acid derivatives)polyvinyl alcohol (PVA) fibres, and synthetic or natural fibrescontaining super absorbing polymers (SAPs). An absorbent materialcomprising two or more of these materials may also be used.

The absorbent material may be provided in any suitable physical form,for example, fibrous form (e.g. for textile materials), compact form(e.g. for mats or tablets made from compressed powders), sheet form(e.g. for cellulosic materials) or fluff (flock) form. For example, inembodiments where the absorbent material is cotton wool, the cotton woolmay be in sheet, woven and/or fluff form. For example, in embodimentswhere the absorbent material is paper pulp, the paper pulp may be insheet or fluff pulp form. For example, in embodiments where theabsorbent material is PVA, the PVA may be in sheet or fibre form. Thesuper absorbent polymers may be spun to yarn, flock or woven and may becross linked with sodium acrylate, acrylic acid or methyl acrylate.

The absorbent material may be of any convenient size. For example, insome embodiments, the dimensions of the absorbent material are selectedto match those of cells of a test container, such that it can snugly fittherein (as described below).

The amount of mercury-containing reagent carried by the absorbentmaterial will depend on factors such as the expected concentration ofthe species in the sample, the volume of the sample, etc. It is withinthe ability of a person skilled in the art to estimate the amount ofmercury-containing reagent required for any given formulation as well asthe corresponding form, size, density and kind of absorbent materialsuitable for a particular application. In some embodiments, for example,these parameters may be selected such that the absorbent material cansnugly fit into a cell of a test kit (described below), rapidly absorbsubstantially all of the urine expected to be introduced into the celland clearly show any resultant colour change.

In some embodiments, for example, the formulation comprises betweenabout 10 and 30 vol % (e.g. between about 15 and 25 vol %, between about15 and 20 vol % or about 20 vol %) of the total volume of the absorbentmaterial. In some embodiments, between about 0.01 and about 5 mL,between about 0.5 and about 3 mL, between about 1 and about 2 mL orbetween about 0.5 to about 1.5 mL (e.g. about 1 mL) of themercury-containing reagent is carried by the absorbent material.

The mercury-containing reagent may be incorporated into the absorbentmaterial in any suitable manner, provided that, once so incorporated,there is substantially no leakage of the mercury containing reagent.Ideally, the absorbent material will be substantially dry, with themercury containing reagent securely held within the material.

In some embodiments, for example, the absorbent material may be soakedin a solution containing the mercury containing reagent for a period oftime sufficient for it to absorb an effective amount of the mercurycontaining reagent. The absorbent material may then be allowed to dry,ether in air or by heating (provided that the mercury-containing reagentis heat stable).

Other Components

The mercury-containing reagent or formulation of the present inventionmay also include other components. For example, some embodiments mayalso include agents such as dispersing agents, solubilising agents,wetting agents or emulsifying agents to improve (or advantageouslyalter) properties of the gel carrier (e.g. its disintegrationproperties) or absorbent material (e.g. its absorbing properties). Forexample:

-   -   dispersing agents can help to quickly disperse the        mercury-containing reagent throughout the patient's fluid        sample, or aid to quickly disperse the gel-carrier;    -   solubilising agents can help to solubilise components in the        formulation and patient's fluid sample, which may enhance any        reactions therebetween;    -   wetting agents can help components in the formulation and        patient's fluid sample to mix, which may enhance any reactions        therebetween; and    -   emulsifying agents can help slightly immiscible components in        the formulation and patient's fluid sample to become more        intimately mixed (and hence enhance any reactions therebetween).

The formulations of the present invention may be provided in anyconvenient form. Given the toxic nature of mercury, however, even thoughthe formulation could be provided in bulk form, it would typically beprovided in unit form in order to minimise handling. For example, anappropriate amount (e.g. volume, in the embodiments where themercury-containing reagent is carried in the gel carrier) of theformulation may be provided in a unit form. Similarly, an appropriateamount (e.g. volume or weight) of the mercury-containing reagent may beprovided a unit sized piece of absorbent material. This unit form may,for example, be provided in its own container (e.g. a vial or ampoule)for subsequent use by the patient or medical practitioner administeringthe test. In some embodiments, the container may be adapted to receive avolume of the fluid sample therein (e.g. so that the appropriate volumeof a urine sample can simply be added to the container, the containersealed and then shaken to disintegrate the gel and enable themercury-containing reagent to react with species in the urine).

The volume of the fluid sample required to detect whether the fluidsample contains the species may vary depending on the nature of thespecies to be detected, its likely concentration in the patient's fluidsample and other factors either known to a person skilled in the art orreadily ascertainable using routine experimentation. In someembodiments, the volume of the fluid sample required to detect whetherthe fluid sample contains the species may vary between about 50-150% ofthe volume of the formulation (e.g. the volume of the fluid sample isabout 50%, 60%, 70%, 80%, 90%, 100%, 110%, 120%, 130%, 140% or 150% ofthe volume of the formulation). If the volume of the fluid sample usedis too low, then the amount of species present may be too low fordetection and/or the gel carrier may not all disintegrate. If the volumeof the fluid sample used is too high, then the resultant precipitate maynot form or may be too dispersed for detection.

For example, in some embodiments, 2-20 mL of a patient's fluid samplemay be mixed with an equivalent volume of the formulation.

Kit

The present invention also provides a kit for detecting a speciesindicative of a disease in a patient. The kit includes amercury-containing reagent which, when contacted with a fluid samplefrom the patient, colourimetrically indicates whether the fluid samplecontains the species, and a non-flowing carrier in which themercury-containing reagent is contained but which, upon exposure to thefluid sample, causes rapid mixing of substantially all of themercury-containing reagent and the fluid sample. The kit also includes acontainer in which the non-flowing carrier and the mercury-containingreagent is contained. The mercury-containing reagent and non-flowingcarrier in this kit may be as described above.

Any container may be used with the kit, provided the non-flowing carrierand mercury-containing reagent can be stably held therein for itsshelf-life (e.g. the container may need to be stable with highly acidicsubstances). The container may be simply used to house themercury-containing reagent and non-flowing carrier until the kit isready for use, whereupon they are transferred to another location. Insome embodiments, for example, the container may be the vial or ampoule,as described above. Such vials or ampoules are, however, more suited foruse by professional medical personnel and, in alternative embodiments,the container may be adapted to be more “user-friendly”, even to theextent of being suitable for use by a patient themselves, as discussedin further detail below.

The container may be adapted to receive the fluid sample from thepatient (e.g. by a patient either directly or indirectly urinating ontothe container). In some embodiments, for example, the container may beadapted to receive a predetermined volume of the fluid sample from thepatient. As would be appreciated, this would help to improve theaccuracy and consistency of test results.

As described herein, it would be advantageous to provide a reliable testfor use by a patient themselves. As such, embodiments of the kit of thepresent invention may be provided in a form that is simple enough forpatients to use at home (e.g. with a urine sample), with instructionsprovided with the kit emphasising the importance of the patient seekingspecialised medical advice in the event of a positive result.

In some embodiments, the container may comprise a plurality of cells,with at least one of the plurality of cells containing the non-flowingcarrier and the mercury-containing reagent; and at least one other ofthe plurality of cells containing a control sample of the non-flowingcarrier that does not contain the mercury-containing reagent. Theplurality of cells are configured to allow a visual comparison of thecolour in each of the plurality of cells.

In such embodiments, a direct visual comparison can be made between atleast two of the cells in the container in order to provide an even morereliable result because factors such as the colour of a patient's urine(for example) or potential colour blindness of the patient (or personassessing the results) are accounted for.

In some embodiments, different amounts of mercury-containing reagent maybe contained in each of the plurality of cells which contain thenon-flowing carrier and the mercury-containing reagent. After exposureto the patient's fluid sample, the gradation in colour across thesecells may provide results indicative of a quantity of the species to bedetected (e.g. tyrosine) in the sample, which may be correlatable with aseverity of the disease.

A specific embodiment of the container for use with the kit of thepresent invention will now be described with reference to FIG. 1. Shownin FIG. 1 is a test device 10, which has a generally rectangular shapewith opposing sides 12, 14 defining gripping portions. The centralportion of device 10 includes a recess 16 that is includes five separatecells (about 5 mL in volume) shown generally as 18, which are divided bywalls shown generally as 20. Rectangular-shaped pads 22 of an absorbentmaterial into which a mercury-containing reagent has been absorbed arelocated at the bottom of three of cells 18. The other two cells 18contain rectangular-shaped pads 24 of the same absorbent material, butwhich contain no mercury-containing reagent. Each pad 22, 24 is shapedto be snugly received within its respective cell 18, so that it isunlikely to fall out of the device 10, even in the event of the device10 being tipped upside down. Walls 20 are slightly lower than a rim 26of the recess 16, for the reasons described below.

In use, a patient would unwrap the device and place it on a stable, flatsurface. The patient would then urinate into a separate cup (not shown),filling it to a prescribed level (e.g. as shown by a level indicator onthe container). The patient may then hold the device 10 in their hand bygripping the opposing sides 12, 14 and then tip the urine from the cupinto the recess 16 which, provided the prescribed amount of urine is inthe cup, will fill the recess 16. Preferably, for the reasons discussedabove, the urine introduced into the device 10 should be from mid-streamduring the patient's first urination of the day. As the walls 20 areslightly lower than the rim 26 of the recess 16, urine will tend to flowfrom one cell 18 into an adjacent cell 18 before it will reach the levelof the rim 26. In this manner, all five cells 18 should become filledwith urine before the urine will reach the rim 26, at which time thedevice 10 is full.

Once full of the patient's urine, the device 10 should be set aside fora prescribed period (e.g. 1-5 mins), during which time the absorbentpads 22, 24 will rapidly absorb the urine. Once the prescribed periodhas expired, the patient simply tips the remaining urine out of thedevice 10 and visually examines the colour of absorbent pads 22, 24. Theresultant colour of absorbent pads 22 is indicative of whether thepatient's urine contains the relevant species (e.g. the pad will haveturned a red colour if tyrosine is present in the patient's urine, inembodiments where the device 10 is being used to detect colorectalcancer). The resultant colour of the absorbent pads 24 may be visuallycontrasted with that of pads 22 in the event of the patient being colourblind or the patient's urine being highly coloured (e.g. as might be thecase if the patient is dehydrated, for example).

In some embodiments, the amount of mercury-containing reagent that is inthe pads 22 may differ in order to provide a gradation in colour for apositive result, which may provide results indicative of a quantity ofthe species to be detected (e.g. tyrosine) in the patient's urine. Insome embodiments, a colour chart (not shown) may also be provided inorder to provide further assistance to the patient in assessing theresults.

As noted above, the present invention also provides a method ofdetecting a species indicative of a disease in a patient. The methodcomprises exposing a fluid sample from the patient to the formulations,absorbent pad or kit of the present invention, and observing the colourof the resultant mixture to determine whether the fluid sample containsthe species.

The fluid sample from the patient may be exposed to the formulationusing any suitable technique, but would most commonly involve adding thefluid sample to the formulation and either shaking the resultant mixture(e.g. in embodiments containing a gel carrier) or allowing the resultantmixture to stand (e.g. in embodiments containing an absorbent material)for an appropriate period of time (e.g. 1-2 minutes). The mixture maythen be left to stand for an appropriate period of time (e.g. 1-5minutes), during which the formation of a coloured product (e.g. a redprecipitate) is indicative of the presence of the species. In someembodiments, it is envisaged that the entire process could take aslittle as about 2, 3, 4, 5, 6 or 7 minutes, and could be carried out bythe patient themselves.

As discussed above, the fluid sample is typically a urine sample fromthe patient. If so, the urine sample is preferably obtained mid-streamfrom the patient's first pass urination. Specialised urine collectiondevices may be utilised for collecting urine samples from a patient.

Also disclosed herein is a kit for detecting a species indicative of adisease in a patient. The kit comprises a container adapted to receive afluid sample from the patient, and which already contains (anappropriate amount of) the formulations of the present invention. Insome embodiments, the kit may also comprise a colour chart for assessingwhether the fluid sample contains the species (i.e. whether the fluidsample is positive or negative to levels of the species indicative of adisease in a patient). In some embodiments, the kit may also comprise aurine collection device, such as that developed by the presentapplicant, for collecting mid-stream urine samples from a patient.

The present invention provides the formulation according to the firstaspect of the present invention for use in detecting a speciesindicative of a disease in a patient.

EXAMPLES Example 1A

A formulation in accordance with an embodiment of the present inventionwas prepared by mixing 2 mL of component (1), 2.4 mL of (2), 0.6 mL of(3) and 0.1mL of (4), where the components are as follows:

-   -   1) 18% solution of mercury sulphate in 6 M sulphuric acid    -   2) 65% solution of mercury nitrate in 12 M nitric acid    -   3) 3% solution of nickel sulphate in distilled water    -   4) 4% solution of 1-nitroso-2-naphthol in 6 M nitric acid

1 mL of this mixture was pipetted into a 7 mL test tube with a 1 mLinsert cap. 1 g of PVP K30 was then added, and the mixture shaken untila gel was formed. The test tube was capped, with the formulation beingready for use.

The formulation was found to be stable (i.e. no liquefying occurred)using an accelerated stability test well known in the art, where thetemperature of the formulation was cycled between 50° C. and −50° C. onan hourly basis for 2 weeks (which is equivalent to a storage stabilityof about 2 years at ambient temperature). When the aged formulation wasadded to an aqueous sample, it completely dissolved in less than 60seconds.

Example 1B

1 mL of the mixture of Example 1A was pipetted into a 7 mL test tubewith a 1 mL insert cap. 1 g of Pluronic F88 was then added, and themixture shaken until a gel was formed. The test tube was capped, withthe formulation being ready for use.

Stability tests similar to those discussed above in Example 1A wereconducted on the formulation, with similar results (i.e. stability anddissolving time) being obtained.

Example 2A

A formulation in accordance with another embodiment of the presentinvention was prepared by mixing 2 mL of component (1), 2.0 mL of (2),1.0 mL of (3) and 0.1 mL of (4), where the components are as follows:

-   -   (1) 18% solution of mercury sulphate in 6 mol sulphuric acid    -   (2) 65% solution of mercury nitrate in 12 mol nitric acid    -   (3) 3% solution of nickel sulphate in distilled water    -   (4) 10% solution of cadmium sulphate in 6 mol nitric acid

1 mL of this mixture was pipetted into a 7 mL test tube with a 1 mLinsert cap. 1 g of PVP K30 was then added, and the mixture shaken untila gel was formed. The test tube was capped, with the formulation beingready for use.

Stability tests similar to those discussed above in Example 1A wereconducted on the formulation, with similar results (i.e. stability anddissolving time) being obtained.

Example 2B

1 mL of the mixture of Example 2 A was pipetted into a 7 mL test tubewith a 1 mL insert cap. 1 g of Pluronic F88 was then added, and themixture shaken until a gel was formed. The test tube was capped, withthe formulation being ready for use.

Stability tests similar to those discussed above in Example 1A wereconducted on the formulation, with similar results (i.e. stability anddissolving time) being obtained.

Example 3

Experiments were conducted to confirm the stability of formulations inaccordance with the present invention under storage conditions, as wellas their ability to rapidly disintegrate upon exposure to a urinesample. In these experiments, the stability and dissolution time of thegel was assessed visually, with the stability being assessed byconfirming that the gel did not liquefy (i.e. before being mixed withthe urine sample) when cycled between temperatures of between −50° C.and 50° C. on an hourly basis for 2 weeks. Total dissolution was definedas the time taken from mixing the formulation/urine sample and shakingfor there to be no visible pieces of gel in the mixture.

Formulations containing the same mercury containing reagent, butdifferent gel carriers were prepared, and their dissolution times andstability were assessed. The results are shown below in Table 1.

TABLE 1 GEL DISSOLUTION STABILITY CARRIER TIME (SECS) (LIQUFYING) PVPK30 45 NONE PLURONIC F88 60 NONE PVPP 90 NONE PAM SAP 40 NONE CMC HV 60NONE

Example 4

In a clinical study the formulation of Example 1A was mixed with firstpass midstream urine specimens from the patients discussed below, shakenand the colour of the resultant mixture assessed with reference to Table2. The patients had separately been diagnosed for the specifiedconditions using conventional techniques (e.g. a colonoscopy forcolorectal cancer), and this clinical study was conducted to assess thereliability of a formulation in accordance with the present invention.

Of 100 patients who had been diagnosed by known methods havingcolorectal cancers, 99 patients showed a strong positive result to theformulation, while one showed a weak positive result. This is equivalentto a 100% detection rate.

Of 36 patients who had been diagnosed with Breast Cancer by knownmethods, 33 patients showed strong positive result to the formulation,while two had weak positive results and one was negative. This isequivalent to a >97% detection rate.

Of 40 patients who had been diagnosed with Bladder Cancer by knownmethods, all of the patients showed a strong positive result to theformulation. This is equivalent to a 100% detection rate.

In these trials, the results were characterised into four categories:negative, weak positive, positive and strong positive. The relevantcategory was determined based on the colour which the formulationchanged to after mixing with the patient's fluid sample, as shown inTable 2. The inventor has conducted extensive trials to confirm that thecolours listed in Table 2 correlate with the recited quantity oftyrosine. A colour chart may also be provided to help distinguishbetween light red, red and bright red (although any form of positiveresult should prompt the patient to seek the advice of a registeredmedical practitioner for further testing).

TABLE 2 TYROSINE COLOR mg/ml STANDARD Light Yellow <3 Negative Light Red 5 ± 1 Weak Positive Red 10 ± 2 Positive Bright Red 15 ± 2 StrongPositive

By way of comparison, 118 normal healthy people were tested duringregular health checks, and the false positive rate was found to be lowerthan 2.54%.

Example 5

The ability of various absorbent materials to absorb and carry themercury containing reagent, and then subsequently absorb urine, wastested in the manner described below. Firstly, the ability of variousabsorbent materials to absorb the reagent and urine solution under freeswell conditions was assessed. Secondly, their ability to retain thereagent and urine when subsequently placed under pressure was assessed.

Materials:

-   -   Absorbent material (see Table 3)    -   Mercury-containing reagent (1 mL)—as per Example 1A    -   Urine sample (5 mL)—separately analysed by HPLC and shown to        contain about 2 mg/mL tyrosine, which is a normal amount of        tyrosine in the urine of an adult male.

Equipment:

-   -   Pyrex Vists 10 mL Griffin Low Form Glass Beaker with a height of        33 mm and an outer diameter of 25 mm    -   Pyrex Buchner Funnel with Sintaglass disc (50 micron pore) 20 mm        diameter    -   Piston to fit the funnel (100 g, 19 mm diameter). Fit a sealing        rubber ring to the piston to avoid leakage of liquid. This        piston is designed to exert 0.5 psi pressure on test material        held within the funnel.    -   Balance (capable of measuring 0.001 g)    -   Stopwatch    -   Steel spatula    -   Surgical gloves (to prevent moisture transfer)

Procedure: A) Mercury-Containing Reagent

-   -   1. Pre-wet the funnel with distilled water and drain thoroughly    -   2. Place 1.0 g of the absorbent material into the sample tube        and record weight as W1    -   3. Add 1 ml mercury-containing reagent and record weight as W2    -   4. Stand wetted absorbent material until reagent has been        absorbed (1 minute)    -   5. Transfer contents of sample tube to the Sintaglass funnel    -   6. Allow non-absorbed mercury-containing reagent to drain into a        pre-weighed tube (W3) for five minutes and record total weight        as W4. Ensure all absorbent material has been transferred using        the steel spatula    -   7. Place the piston (without exerting pressure) on the remaining        absorbent material    -   8. Drain for further five minutes under the piston-load into the        pre-weighted tube    -   9. Measure the total weight of mercury-containing reagent in the        pre-weighed tube along with any that has exuded past the piston        and record as W5.    -   10. Record visible appearance of the mercury-containing reagent        on the absorbent material        B) Urine on Absorbent Material Containing 1 mL        Mercury-Containing Reagent (i.e. Prepared as Per Method A))    -   1. Pre-wet the funnel with distilled water and drain thoroughly    -   2. Place the material with reagent in into the sample tube and        record as R1    -   3. Add 5 ml urine and record as R2    -   4. Stand wetted material until the urine has been absorbed (2        minute)    -   5. Transfer contents of sample tube to the Sintaglass funnel    -   6. Allow non-absorbed urine to drain into a pre-weighed tube        (R3) for five minutes and record total weight as R4. Ensure all        material has been transferred using the steel spatula    -   7. Place the piston (without exerting pressure) on the remaining        material    -   8. Drain for further five minutes under the piston-load into the        pre-weighted tube    -   9. Measure the total weight of urine in the pre-weighed tube        along with any that has exuded past the piston and record as R5.    -   10. Record visible appearance of urine on the absorbent material

Calculations:

-   -   Reagent:    -   Free swell (g/g) is calculated as: (W2−[W4−W3])/W1    -   Retention (g/g) is calculated as: (W2−[W5−W3])/W1

Urine:

Free swell (g/g) is calculated as: (R2−[R4−R3])/R1

-   -   Retention (g/g) is calculated as: (R2−[R5−R3])/R1

TABLE 3 Time (secs) Time (secs) for total for total Visual Free SwellRetention absorption Visual Free Swell Retention absorption (afterreagent) (after reagent) (after reagent) of reagent (after urine) (afterurine) (after urine) of urine Paper Pulp Dry 1 1 5 Film on Top 1.33 1.2545 Cotton Wool Dry 1 1 5 Film on Top 1.33 1.25 40 Bleached Bamboo Dry 11 5 Thick Film 1.6 1.5 60 Synthetic Microfiber Dry 1 1 Instant Dry 1 130 SAP Flock Dry 1 1 Instant Dry 1 1 20 PVA Flock Dry 1 1 Instant Dry 11 20

These results show that the exemplified kinds of absorbent materials allvery rapidly absorb the reagent with very little swelling and retain thereagent therein, even when subjected to significant amounts of pressure.The absorbent materials also rapidly (less than a min) absorb the urine.The colour of the absorbent material after it had absorbed the urine wasa typical yellowish urine colour, as would be expected because the urinedid not contain elevated levels of tyrosine.

Example 6

A number of clinical trials were conducted in order to confirm that theabsorbent pads described herein are suitable carriers for amercury-containing reagent and for use in the present invention. Inthese clinical trial, urine from a variety of patients was added to acontainer including 4-6 cells, in each of which resided an absorbent padcomprising a super-absorbent polymer. Some of the absorbent pads wereplacebos, as described above, other absorbent pads carried themercury-containing reagent of Example 1A.

An 88 yo female presented with mild iron deficiency but normalhaemoglobin levels. A FOBT (faecal occult blood test) had also returneda positive result. Her urine sample was analysed and returned appositiveresult (positive colour change in one of the cells), indicating a highrisk of malignancy and therefore more urgent investigation wasinitiated. A colonoscopy showed that the patient had stage 1 coloncancer (adenocarcinoma).

A 57 yo patient presented with iron deficiency anaemia. Their CEA wasnormal and a CT scan of their abdomen/pelvis showed no acute distress.However, a mildly positive result was returned using the test of thepresent invention, indicating urgency for further investigation. Asubsequent colonoscopy revealed large proximal transverse 8×3 cm polypwhich was removed endoscopically. Histology revealed a small focus ofmoderately differentiated adenocarcinoma so surgery recommended to clearregion. Subsequent right hemicolectomy revealed small residual cancerStage 1

A 75 year old male patient with stage 3B colon cancer returned apositive FOB test as well as a positive result using the test of thepresent invention. An urgent colonoscopy was conducted, which revealedulcerating sigmoid cancer requiring left hemicolectomy. Their CEA wasalso elevated 11 (0-5) and a CT scan showed sigmoid cancer andsuspicious liver nodules, possibly metastases.

An 85 yo male presented with diarrhoea & weight loss. A CT scan showedsigmoid thickening with suspicious liver metastases. His urine wasanalysed and returned appositive result (positive colour change in oneof the cells). Subsequent surgery confirmed metastatic peritonealadenocarcinoma (stage 4).

A 73 yo male presented with anaemia and melena whilst on Xarelto for AF.He returned negative PET and CT scans. However, his urine was analysedand returned appositive result (positive colour change in one of thecells). A subsequent gastroscopy revealed 5 cm gastric adenocarcinomaand will undergo neo adjuvant chemotherapy before future surgery.

A 69 yo female presented with sudden weight loss & Iron deficiencyanaemia. CT scans showed metastatic liver disease with omentalmetastases and right colonic wall thickening and possible renal cellcancer. Her urine was analysed and returned appositive result (positivecolour change in one of the cells). A subsequent colonoscopy revealedright colon cancer—adenocarcinoma.

An 85 yo male with metastatic gallbladder cancer had an incidentaltumour found by a CT scan performed because of new onset constipation.However, a follow up gall bladder polyp—colonoscopy was normal. Thepolyp grew in size from 4 mm to 25 mm over 18mnths but was asymptomatic.However, his urine was analysed and returned appositive result (positivecolour change in one of the cells). Surgery subsequently confirmedgallbladder adenocarcinoma.

A 58 yo male's urine returned a positive result (positive colour changein one of the cells). A subsequent colonoscopy revealed malignantlooking rectal polyp, which was completely removed endoscopically withonly a focus of adenocarcinoma. His CEA was normal, and a CT scan of hisabdo/pelvis and an Mill of his rectum were all normal. His PSA waselevated 6.0 (0-3.5). Further investigation pending.

It will be appreciated that the present invention provides a number ofnew and useful results and advantages over existing diagnostic tests.For example, specific embodiments of the present invention may provideone or more of the following advantages:

-   -   the mercury-containing reagent is safely contained within the        gel or absorbent material;    -   reliable results can be obtained due to the rapid mixing of the        mercury-containing reagent and fluid sample (no        second-guessing);    -   the container does not necessarily need to be glass—plastic        containers may be used (even if the mercury-containing reagent        is highly acidic);    -   the container can be provided in the form of a urine collection        device, making it even simpler to use;    -   regulatory approval is likely to be simpler to obtain because        the test is only indicative of a potential disease or condition,        with the patient needing to seek professional medical advice in        the event of a positive result; and    -   testing can be performed by people with relatively little (or        no) medical training—e.g. the patient themselves.

It will be understood to persons skilled in the art of the presentinvention that many modifications may be made to the embodiments of thepresent invention specifically described above without departing fromthe spirit and scope of the invention. All such modifications areintended to fall within the scope of the following claims.

It will be also understood that whilst the preceding description refersto specific pieces of apparatus and equipment and sequences of methodsteps, these are provided for illustrative purposes only and are notintended to limit the scope of the present invention in any way.

It is to be understood that reference to any prior art publicationreferred to herein does not constitute an admission that thatpublication forms a part of the common general knowledge in the art, inAustralia or any other country.

In the claims which follow and in the preceding description of theinvention, except where the context requires otherwise due to expresslanguage or necessary implication, the word “comprise” or variationssuch as “comprises” or “comprising” is used in an inclusive sense, i.e.to specify the presence of the stated features but not to preclude thepresence or addition of further features in various embodiments of theinvention.

What is claimed is:
 1. A formulation for detecting a species indicativeof a disease in a patient, the formulation comprising: amercury-containing reagent which, when contacted with a fluid samplefrom the patient, colourimetrically indicates whether the fluid samplecontains the species, wherein the mercury-containing reagent iscontained within a non-flowing carrier which, upon exposure to the fluidsample, causes rapid mixing of substantially all of themercury-containing reagent and the fluid sample.
 2. The formulation ofclaim 1, wherein the non-flowing carrier is a gel carrier which, uponexposure to the fluid sample, rapidly disintegrates to releasesubstantially all of the mercury-containing reagent.
 3. The formulationof claim 2, wherein the gel carrier disintegrates to releasesubstantially all of the mercury-containing reagent within less thanabout 1 minute after being exposed to the fluid sample.
 4. Theformulation of claim 2, wherein the gel carrier has a viscosity ofbetween about 50,000 and about 1,000,000 cps.
 5. The formulation ofclaim 2, wherein the gel carrier is a hydrogel.
 6. The formulation ofclaim 2, wherein the gel carrier is formed from any one of thefollowing: polyacrylamides, carboxy methylcellulose, polyvinyl alcohol,poly(acrylamide-co-maleic acid), poly(vinylpyrrolidone), alginates,carbomers, polyoximers, natural and synthetic gums, and mixturesthereof.
 7. The formulation of claim 2, wherein the formulationcomprises between about 20 and 80 vol % of the gel carrier.
 8. Theformulation of claim 1, wherein the non-flowing carrier is an absorbentmaterial which, upon exposure to the fluid sample, rapidly absorbs thefluid sample.
 9. The formulation of claim 8, wherein the absorbentmaterial absorbs the fluid sample within less than about 1 minute afterbeing exposed to the fluid sample.
 10. The formulation of claim 8,wherein the absorbent material is a fibrous material.
 11. Theformulation of claim 8, wherein the absorbent material is formed fromany one or more of the following: paper pulp, cotton wool, cellulosicfibres, synthetic fibres, super absorbent polymers and polyvinyl alcoholfibres.
 12. The formulation of claim 8, wherein the formulationcomprises between about 10 and 30 vol % of the total volume of theabsorbent material.
 13. The formulation of claim 1, wherein themercury-containing reagent comprises mercury dissolved in an acidsolution.
 14. The formulation of claim 1, wherein the mercury-containingreagent comprises a source of Hg⁺ ions and a source of Hg²⁺ ions in anacid solution.
 15. The formulation of claim 14, wherein themercury-containing reagent further comprises one or more of thefollowing: a source of Ni²⁺ ions, a source of Cd²⁺ ions,1-nitroso-2-naphthol, a diazonium compound and an Azo compound.
 16. Theformulation of claim 1, wherein the formulation further comprises one ormore of the following agents contained within the non-flowing carrier:dispersing agents, solubilising agents, wetting agents, emulsifyingagents and combinations thereof.
 17. The formulation of claim 1, whereina volume of the formulation is provided in a unit form.
 18. Theformulation of claim 1, wherein the fluid sample is a urine sample fromthe patient.
 19. The formulation of claim 1, wherein the speciesindicative of a disease in a patient is tyrosine.
 20. The formulation ofclaim 19, wherein the disease is a cancer.
 21. A formulation fordetecting a species indicative of a disease in a patient, theformulation comprising: a mercury-containing reagent which, whencontacted with a fluid sample from the patient, colourimetricallyindicates whether the fluid sample contains the species; and a gelcarrier in which the mercury-containing reagent is contained but which,upon exposure to the fluid sample, rapidly disintegrates to releasesubstantially all of the mercury-containing reagent.
 22. An absorbentpad for detecting a species indicative of a disease in a patient, thepad comprising: an absorbent material adapted to rapidly absorb a fluidsample from the patient; a mercury-containing reagent contained withinthe absorbent material, the mercury-containing reagent being capable ofcolourimetrically indicating whether the fluid sample from the patientcontains the species upon contact with the fluid sample, whereby, uponexposure of the pad to the fluid sample, the absorbent material rapidlyabsorbs the fluid sample thereby causing rapid mixing of substantiallyall of the mercury-containing reagent and the fluid sample.
 23. A kitfor detecting a species indicative of a disease in a patient, the kitcomprising: a mercury-containing reagent which, when contacted with afluid sample from the patient, colourimetrically indicates whether thefluid sample contains the species; a non-flowing carrier in which themercury-containing reagent is contained but which, upon exposure to thefluid sample, causes rapid mixing of substantially all of themercury-containing reagent and the fluid sample; and a container inwhich the non-flowing carrier and the mercury-containing reagent iscontained.